將varchar值'Truck'轉換爲數據類型位時轉換失敗

Question

當我試圖運行下面的查詢時。它工作得很好。

SELECT DelayId, DelayCategory, DelayReason FROM 
[TAMS].[DelayMaintenance] 
WHERE IsUtilized = 1 
AND Truck = 1 
union  SELECT 0, NULL, '--- Pick One----' 
ORDER BY DelayId 

但是，當我試圖使用在相同的查詢，但參數。它給了我一個錯誤。

Msg 245, Level 16, State 1, Line 4 
Conversion failed when converting the varchar value 'Truck' to data type bit. 

DECLARE @CheckPointType VARCHAR(50) = 'Truck' 
DECLARE @BitConveyance BIT = 1 

SELECT DelayId, DelayCategory, DelayReason FROM 
[TAMS].[DelayMaintenance] 
WHERE IsUtilized = 1 
AND @CheckPointType = @BitConveyance -- Issue is here 
union  SELECT 0, NULL, '--- Pick One----' 
ORDER BY DelayId 

Answer 1

正如@Lamak暗示的那樣，您需要使用動態SQL。像這樣的東西可能會工作

DECLARE @CheckPointType VARCHAR(50) = 'Truck' 
DECLARE @BitConveyance BIT = 1 
DECLARE @SQL NVARCHAR(MAX) 

SET @SQL = 'SELECT DelayId, DelayCategory, DelayReason FROM [TAMS].[DelayMaintenance] WHERE IsUtilized = 1 AND ' + @CheckPointType + ' = ' + CAST(@BitConveyance AS CHAR(1)) + 
      ' union  SELECT 0, NULL, ''--- Pick One----'' ORDER BY DelayId' 

EXEC (@SQL)